The RMT said the union’s executive had decided to suspend the strike, after the TSSA earlier called off its action.

Virgin trains, which runs services on the East and West Coast mainlines, tweeted: “As a result of planned industrial action being cancelled, the original timetabled services have been reinstated for 25th & 26th May.”

Union negotiators had been involved in four days of talks with Network Rail at conciliation service Acas.

RMT general secretary Mick Cash said: “RMT has received a revised offer that enables us to suspend the planned industrial action while we consult in full with our Network Rail representatives.”

Manuel Cortes, general secretary of the TSSA, said: “Our negotiating team at Acas has received a revised offer from Network Rail.

“As a result of this, they have suspended the planned industrial action, pending the outcome of a meeting of our workplace representatives next week.”

Lawyers for Network Rail halted plans to take legal action against the TSSA, over the way its ballot had been conducted, in the light of developments.